Levi's Daughter?

Mission?

I woke up in a fancy room, if that. It was different from the other rooms and looked alot better. I couldn't remember what happened to me and my head was still in a blur.

I tried to sit up but something was stopping me from doing so. I turned around and saw a chain that was on my arms. The chain got lost somewhere underneath the bed that I was sat on. I struggled to take the chain off but it just made really loud noises, after a few attempts I just gave up and and I leaned back to try and think of another way off of them.

The door opened slightly and someone popped their head into the room. I wasn't able to see their face but it was only a second before they ran off.

A few minutes later I heard the door open again and I saw him.
Erwin.
He was smirking like always.
Just standing.

I looked around the room to see if he had taken my gear and left it in the room but my gear was no where to be seen.

Now he was coming closer to me and the only thing I could say was:
'Stop! Don't come any closer or I'll-.'
I stopped.
'Or you'll what?'
He was laughing, he found this amusing.

Before I could reply I saw the door fly open and a small figure walk in though the door.
He looked angry.
Really angry.
Uncle Levi stood still with his dark, cold eyes pinned on Erwin.
Silence.
Nothing broke the silence.

Until Erwin decided to take one more step closer to me.

That's when Uncle Levi lost it.
In a second uncle Levi was in Erwin's face, it was too fast to see.
Next second I knew Erwin was on the floor and the chains were off my arms.

We were about to leave until Erwin said:
'Don't forget about the mission coming Levi. Better make sure she's up for it.'
With that he let out a little chuckle and uncle Levi just looked at him before we turned away towards the door.
We left the room.
While walking I asked uncle Levi:
'Who's room where we in just now?'
Uncle Levi took a while to answer but finally said:
'Erwin, we where in Erwin's room.'
With that I stopped.
'Erwin's room?'...

What mission was he talking about? It has to do with going out of the walls to those things doesn't it? Why did Erwin wait until now to mention it?